White (Sweet) Miso

Miso is an umami-rich paste made by mixing beans (historically, soybeans), salt, and koji, a grain (usually rice) which has been inoculated and fermented with a mold, Aspergillus oryzae. The flavor and complexity of miso is unmatched even compared to other fermented dishes. It is at once savory, sweet, salty, and powerful.

White miso is lighter and sweeter than its more popular and traditional cousin, red miso (akamiso). That’s due to the shorter fermentation time, and higher ratio of koji (which is carbohydrate rich and produces a sweeter finished product). Many modern commercial white misos are “cooked” rather than fermented, creating a finished product in a matter of days, not weeks.

Aspergillus oryzae under microscope

The easiest way to start making miso is to buy pre-made dried koji, grains (rice or barley) which have been inoculated with the A. oryzae mold culture. Local Asian markets usually carry dried “firm granular” koji. You can also find online merchants like this one.

The making of miso…


White Miso
Prep time
Fermentation time
Yield: 2 quarts/2 liters
  • 10.5 oz (by weight)/ 300g dry beans (lentils, chickpeas, adzuki, black beans or other legumes)
  • 20 ounces (by weight) /567g dried firm granular koji (1 tub)
  • 2.5 oz (by weight)/70g sea salt
  • filtered water
  • 1 Tablespoon/15 ml mature miso
  • 2 quart-size or 1 half-gallon or larger glass or ceramic vessel
  • For ceramic crock: jar or wine bottle which fits inside mouth of vessel
  • dish or tea towel
  • rubber bands or twist ties
  • OR Small batch fermentation kit with airlock and weight
  1. [All beans other than lentils] Soak beans in filtered water overnight (up to 24 hours).
  2. Drain beans from soaking liquid. Rinse well.
  3. Bring beans and enough filtered water to cover beans to a boil, then reduce heat to simmer.
  4. Cook beans for 45 to 60 minutes, or until done.
  5. Drain beans, RESERVING 2 cups/ 600ml of the cooking liquid.
  6. Add beans to a large mixing bowl.
  7. Mash the beans, leaving them somewhat chunky (almost as smooth as refried beans).
  8. Dissolve salt in reserved cooking liquid. Let brine mixture cool to 100°F/38°C or below.
  9. Add mature miso to the brine. Stir until incorporated.
  10. In a separate bowl, add brine and then stir in koji.
  11. Add koji-brine mixture into beans. Mix well.
  12. Pack the vessels with the bean/koji mixture, ensuring there are no air bubbles in the mixture (they can breed bad mold!) Use sauerkraut pounder or tap vessel on a towel or wooden cutting board several times to ensure that any air bubbles in the mixture come to the surface.
  13. Add a weight such as a glass bottle or plate to the top of the mixture. This will weigh it down and allow the tamari to rise to the surface.
  14. Or use small-batch fermentation weights and lids to secure the jar(s).
  15. If not using fermentation tools, cover container with a dish towel or tea towel to keep flies and dust away. Secure with a rubber band, twist ties or elastic strap. Stash it in a cool, dark place– a cellar, under the stairs, or under the sink in the kitchen.
  16. Store it in an unheated space (like the garage) for 4 to 6 weeks.
  1. Carefully unwrap the vessel. Drain the tamari (if any liquid is formed on the top) into another bowl and then into a bottle. Cherish this!
  2. Remove the weight. Scoop out any funky mold from the top surface.
  3. If fermented in a crock, transfer miso into glass jars. To store, use a layer of parchment or wax paper between the metal lid and the lip of the jar (miso corrodes metal).
  4. For longest life, store in the refrigerator.




Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.